It harks all the way back to the first days of the comanche club. It wasn't always like it is now... It used to be an email type forum on yahoo, where threads would be like a long email, replied to a million times. I used to always sign off with my name and initial to designate where my post ended, since it was sometimes hard to see.
I still do it out of habit, and its one of the ways I just finish up a post. I find it a little more personal to sign off like that. Also, in PM's, I will drop the L. if I believe the recipient and myself are friends... Don't ask why, just something I do.
Rob L.